1-p-dimethylaminophenyl-3.4.4-trimethyl-5-pyrazolone and process of making same.



STATES PATENT OFFICE.

FRIEDRICH s'roL-z, or HocHsT-oN-THE-Mam, GERL ANY, ASSIGNOR TOFARBWERK-E VORM. MEISTER LUoIUs & BRtJ'NING', .OF HoeHsT-oN-THE-MAIN,GERMANY, a con- PORATION OF GERMANY.

1rmxmnrmrnAmmornnnnc.4.@rRIMErHYIJ-PYIiAzoLoNE 1m; lnocnss. or

MAKING SAME.

No Drawing;

To all-whom it mayjcon cem.

Be it. known that I, FRIEDRIQH Strong Ph. I1, chemist, a citizen of theEmpire'- of Germany, residing at HESchSt-on-the- Main, Germany, have,inventedcertain new. and useful Improvements in-1-P-Dnnethylaminophenylriisk l Triniethyl Pyrazolofne and Processes ofMaking Same, of Which the following is a specification.

I haye'found that a new compound of great "value owingto its antipyreticaction can be obtained by, methyla-ting the 1-19;

aIninophenyl-3. iat-triinethyl 5 pyraz olon e.

'This new C01D13011'11dl1121y"b8 designated l-' paradimethylaniinophenyl ii.lA-trimethyL- 5-py'razolone.

Thel -p-a minofihenyl-di l tri'rnethyl 5 pyrazolone can belproducedfroin l-phenyl- 3,4.4c trimethyl-5pyrazolone by. the action of,concentrated nitric acid in presence.

ofconcentrated sulfuric acid and subse- "qilent reduction of thereSuIt-ing-"nitmphenylt-t'i methylpyrazolone by means of tin andhydrochloric acid.

dimethyl-sulfate are particularly suitable for the methylation of theamino compound, 4

but there may also ,be used other processes for the introduction ofthemethyl groups.

In order to illustrate the process more fully the following example isgiven :-1OO 1 parts by weight of 1-phenyl-3.4.4-trnnethylfi-pyrazoloneare dissolyed'at'I0 20"C. in

700 parts of concentrated 'sulfricacidL, There are thenadded drop bydrop at 015!) +596; While stirring, 125 parts of--a,,mixe

ture of fuming-nitric acid and-concentrated sulfuric acid,containing-"26 cent. of

NO H. The" product of the reaction is poured in ice-'Waterand the1preclpltate of l--p.nitrophenyl3. 4.4-trimethy -5'-pyrazol.one

thus-formed -1s filtered OE and washed with, Water.- Byrecrystallization from alcohol the nit-r0 derivative is obtainedin theform I of faint-yellow. needles,- melting at 126 C insoluble in Waterand diluted acids.

100 parts by Weight of 1-p.nitr0phenyl-3.

4;4-trimethyl-fi-pyrazolone are poured over with 400 partsofconcentrated 'hydrocl'iloric Specification of Iletter's Patent.

acid and then there are gradually added.

'While stirring, 115

Methyl-iodid jor Patented Feb. 20, 1912.

Abplication filed June is, i911. Serial No. 632,912.

parts of tin, Where'upo'n the-mass is heated! until'all vthetin isdissolved- After having diluted the mass with Water, the dissolved tinis precipitatedby means of hydrogen sulfid, and the filtratie' of thetin sulfid is evaporated- After cooling, 'the chlorhydrate of'the-1-p.-aminophe-- nyl-3. tA-trimethyl-5-pyr azolone" crystallizes out andfrom this the free base is precipitated by'nieans of caustiosoda-lye, atfirst as anoily mass which, on stirring, becomes a white crystallinepowder. 1 By recrystalli-,

zat ion' from benzene-ligroin the p-aminophenyltrimethylpyrazolone isobtained in the'form of white needles',=melting at 116 It is insolublein Water. but readily 'soluble-i'n diluted acids, and its acid solutionmaybe diazotized by means of nitrous acid;

100 parts'by weight of l para-aminophenyl-3AA-trin1ethyl 5 pyrazoloneare heated With-T0 parts of methyl-iodidand parts =01" Inethylalcoholfor 68 hours to 90400 C. After distilling the alcohol the residue.

dissolved in water. "The solution thus obtained is o'versaturated withalkali and the resulting dimethyla ninopheny]trimet-hylpyrazoloneis-extracted by shaking with ether. Thebase, remaining after.distillation of the solvent as an oily mass, soon solidifies into acrystalline mass. By recrystalli'zation' frorn dilut'ed'alcohol, White.crystals are obtained, melting at- 5 S 59 C.

The methyl-5 -pyra'zolone is-difiicultly soluble in v 1- -dimethylaniinophenyl 3. tA ti-i-' Water, readily soluble in'a'lcohoL-et-her and benzene. IVhen treated with hydrochloric "acid' itforms a Well crystallizingsalt readthe soIution of itschlorhydrate inWater as-- In testimony whereof, I afiix my signature sufininlgi byalddition of ferric chlorid a blnin presence of'two witnesses. is -vioet 00 or.- 1 ,1

2. Theprocess of manufacturin .l-p-di- FRIEDRICH SLOLZ' 51nethy1a1n1n0phenyL3.LA-triniethyl S-pyraz- Witnesses:

olone, which consist-s in methylating 1-p- JEAN Gmmn,aminophenyi-3.LA-trimethyl-5 pyraz010ne. CARL GRUND.

